Fluorine-containing elastomers are widely used in the fields of automobile industry, semiconductor industry and chemical industry because they exhibit excellent chemical resistance, solvent resistance and heat resistance. For example, in the field of automobile industry, fluorine-containing elastomers are used as a hose, a sealing material and the like for an engine and peripheral equipment thereof, and automatic transmission (AT) equipment, fuel system and peripheral equipment thereof.
On the other hand, in compounding of components of fluorine-containing elastomer compositions of a polyol crosslinking system which is generally adopted, blending of calcium hydroxide to the compositions has been carried out to accelerate crosslinking (for example, refer to JP52-15543A and Takaomi Satokawa, “Fluorine-containing Resin Handbook”, First Edition, Nikkan Kogyo Shuppan Production, Nov. 30, 1990, p. 567).
However, in a polyol-crosslinkable fluorine-containing elastomer composition, it is known that when an elastomer molded article comprising calcium hydroxide comes into contact with fuels (especially biofuels), chemicals and solvents (especially acidic solvents), decomposition and deterioration of such fuels and the like occur. Among these fuels and the like, biofuels (for example, biodiesel, etc.) produced from oils derived from living beings is easily oxidized and deteriorated in the presence of calcium hydroxide, and then a polyol-crosslinkable fluorine-containing elastomer composition after coming into contact with the deteriorated biofuel is also greatly subject to deterioration and swelling. There is no problem when an amount of calcium hydroxide is deceased or it is not blended. However, in the case of using no calcium hydroxide, a crosslinking speed is greatly decreased, which is not practicable. Therefore, the present situation is such that calcium hydroxide is blended.